North Macedonia's former parliament speaker, intelligence chief and two ex-ministers were sentenced Monday to six years in prison for plotting the 2017 attack on parliament in Skopje.

Several MPs, including opposition leader Zoran Zaev who is now the Balkan country's prime minister, were severely beaten when a crowd of demonstrators stormed the parliament on April 27, 2017.

The protesters, who supported the conservative VMRO-DPMNE party, opposed a proposed coalition government between Zaev's Social Democrats and ethnic Albanians, which they perceived as a threat to national unity.

According to the court verdict, former speaker Trajko Veljanoski deliberately prolonged the session while two ministers, Risto Spirovski and Mile Janakieski, communicated with organisers of the crowd outside the parliament.

All were from the VMRO-DPMNE party.

The court also sentenced the former director of North Macedonia's secret service Vladimir Atanasovski for being a direct organiser of the unrest, saying he ordered a car full of weapons to be brought near the parliament building.

Together they "organised and materially supported the mass protests that culminated in a violent entrance in the parliament", presiding judge Ile Trpkov said.

The officials were all sentenced for undermining the country's constitutional order, but can still appeal.

The court also accused former conservative prime minister Nikola Gruevski, who ruled the country from 2006 to 2016, of being part of the group plotting the attack.

But he was not tried as he has since fled to Hungary where he received political asylum.